Method and apparatus for contactless yarn monitoring in a spinning or bobbin winding machine

An apparatus for performing contactless yarn monitoring in a textile yarn winding operation wherein a yarn is wound on a bobbin while being delivered lengthwise in a yarn travel direction toward the bobbin and simultaneously executing traversing motions generally perpendicular to the yarn travel direction, the apparatus comprising:

• a sensor device for detecting a measured value other than presence or position of the yarn, the sensor device having a measurement region wherein the moving yarn is subject to changes of position in the measurement region,
• correction-value ascertainment means for determining correction values corresponding to measurement errors caused by changes of position of the yarn,
• position-determining means for determining at least one instantaneous position of the moving yarn in the measurement region, and
• compensation means for compensating for the applicable measurement error for the detected measured value on the basis of the instantaneous position of the yarn.

In a textile yarn winding operation wherein a yarn is wound on a bobbin while being delivered lengthwise in a yarn travel direction toward the bobbin and simultaneously executing traversing motions generally perpendicular to the yarn travel direction, a method for contactless monitoring of the yarn comprising:

• providing a sensor device for detecting a measured value of a yarn quality of the yarn moving in the yarn travel direction, wherein the sensor device has a measurement region, and wherein the moving yarn is subject to changes of position in the measurement region of the sensor device,
• ascertaining a position-dependent correction value corresponding to measurement errors caused by changes of position of the yarn,
• storing the position-dependent correction value,
• monitoring the position of the yarn in the measurement region,
• determining an instantaneous position of the yarn, and
• compensating for the applicable measurement error on the basis of the instantaneous position of the yarn by linking the position-dependent correction value with the measured value detected at the instantaneous position of the yarn;
• whereby the correction value is determined empirically from measurements performed utilizing a comparison body located at different positions distributed within the measurement region of the sensor device.

In a textile yarn winding operation wherein a yarn is wound on a bobbin while being delivered lengthwise in a yarn travel direction toward the bobbin and simultaneously executing traversing motions generally perpendicular to the yarn travel direction, a method for contactless monitoring of the yarn comprising:

• providing a sensor device for detecting a measured value of a yarn quality of the yarn moving in the yarn travel direction, wherein the sensor device has a measurement region, and wherein the moving yarn is subject to changes of position in the measurement region of the sensor device,
• ascertaining a position-dependent correction value corresponding to measurement errors caused by changes of position of the yarn,
• storing the position-dependent correction value,
• monitoring the position of the yarn in the measurement region,
• determining an instantaneous position of the yarn,
• compensating for the applicable measurement error on the basis of the instantaneous position of the yarn by linking the position-dependent correction value with the measured value detected at the instantaneous position of the yarn, and
• causing the yarn to move in a yarn travel path having a first location at which no traversing motion of the yarn occurs, and a second location at which the yarn executes the traversing motion, ascertaining the position-dependent correction value by making a respective first measurement at the first location along the yarn travel path, making a second measurement at the second location along the yarn travel path, and comparing the applicable measurement results with one another, wherein both measurements take place at the same location on the moving yarn.

In a textile yarn winding operation wherein a yarn is wound on a bobbin while being delivered lengthwise in a yarn travel direction toward the bobbin and simultaneously executing traversing motions generally perpendicular to the yarn travel direction, a method for contactless monitoring of the yarn comprising:

• providing a sensor device for detecting a measured value of a yarn quality of the yarn moving in the yarn travel direction, wherein the sensor device has a measurement region, and wherein the moving yarn is subject to changes of position in the measurement region of the sensor device, the sensor device comprising a yarn monitor for monitoring movement of the yarn and a yarn cleaner to correct imperfections in the yarn;
• ascertaining a position-dependent correction value corresponding to measurement errors caused by changes of position of the yarn,
• storing the position-dependent correction value,
• monitoring the position of the yarn in the measurement region,
• determining an instantaneous position of the yarn, and
• compensating for the applicable measurement error on the basis of the instantaneous position of the yarn by linking the position-dependent correction value with the measured value detected at the instantaneous position of the yarn.

In a textile yarn winding operation wherein a yarn is wound on a bobbin while being delivered lengthwise in a yarn travel direction toward the bobbin and simultaneously executing traversing motions generally perpendicular to the yarn travel direction, a method for contactless monitoring of the yarn comprising:

• providing a sensor device for detecting a diameter of the yarn moving in the yarn travel direction, wherein the sensor device has a measurement region, and wherein the moving yarn is subject to changes of position in the measurement region of the sensor device,
• ascertaining a position-dependent correction value corresponding to measurement errors caused by changes of position of the yarn,
• storing the position-dependent correction value,
• monitoring the position of the yarn in the measurement region,
• determining an instantaneous position of the yarn, and
• compensating for the applicable measurement error on the basis of the instantaneous position of the yarn by linking the position-dependent correction value with the diameter detected at the instantaneous position of the yarn.